KR20100125772A - Cleaner composition for removal of lead-free soldering flux - Google Patents

Abstract

The present invention

(a) a polymethyl alkyl siloxane surfactant represented by the following formula (1);

(b) tetrahydrofurfuryl alcohol represented by the following formula (2); And

(c) a lead-free solder flux removal cleaning composition comprising a non-halogen organic solvent:

[Formula 1]

Where

R ₁ is hydrogen or an alkyl group having 1 to 8 carbon atoms.

(2)

Description

Lead-free solder flux cleaner composition {CLEANER COMPOSITION FOR REMOVAL OF LEAD-FREE SOLDERING FLUX}

The present invention relates to a lead-free solder flux detergent composition.

When manufacturing precision parts, such as an electronic component and a semiconductor component, soldering is normally performed. Conventionally, the process solder containing lead is used for soldering. Usually, the solder contains flux. The flux cleans the solder surface and the object on which the solder is performed and improves the wettability of the solder to the object. For this reason, the solder containing the said flux improves the bonding strength of a solder and a soldering object. The flux is usually composed of base resins such as rosin and rosin derivatives, active agents such as organic acids and halides, and solvents such as alcohols.

After soldering, a cleaning process is performed to remove excess solder flux remaining on the surface of the part. In this washing step, a chlorine-based cleaner mainly composed of chlorine-based solvents such as trichloroethylene, perchloroethylene, and methylene chloride was used. The chlorine-based cleaner has the advantage of being nonflammable and excellent in dryness. However, the cleaning agent is currently limited in use due to environmental problems such as ozone layer destruction, soil pollution, toxicity to the human body, etc., and is also used for cleaning ionic residues such as chlorine ions and sulfate ions. There is a disadvantage in that there is almost no cleaning effect.

Japanese Patent Publication No. 10-2008-0114718 discloses a non-halogen-based detergent composition containing specific glycol ethers, nonionic surfactants, and polyoxyalkylene phosphate ester surfactants as essential components. In addition, Japanese Patent No. 2813862 discloses a non-halogen-based detergent composition in which a polyoxyalkylene amine-based surfactant is further added to the detergent composition.

These detergent compositions have excellent cleaning power (particularly, cleaning power against ionic residues), and have low toxicity, odor, flammability, and effects on the object to be cleaned (for example, corrosion of the object being cleaned). It is known to be suitable as a composition for removing solder flux adhering to precision parts such as electronic parts and ceramic parts.

However, in recent years, due to the recognition of the harmfulness of lead, the use of solder, including lead is limited in countries around the world, lead-free solder using copper, silver, etc. in place of the lead has been actively used. Examples of lead-free solders include alloys such as tin-silver, tin-copper, and tin-silver-copper.

When lead-free solder is used, the welding temperature should be 30 ° C or higher (except for some alloy-based lead-free solder), compared to the case of using conventional tin-lead solder, and the solder wettability is higher than that of the conventional tin-lead solder. There is a problem that falls. In order to solve this problem, an active agent is used which increases the content of the active agent in the lead-free solder or is stronger than the active agent used in the conventional lead-free solder.

However, when such lead-free solders are used, many reaction products tend to occur during the welding process. Examples of the reaction product include salts of the activator and tin, and salts of rosin and tin when rosin-based flux is used. Such reaction products are difficult to remove from the object to be cleaned because they are difficult to dissolve in various solvents, cleaning compositions, water, and the like as tin divalent or tetravalent metal salts. Specifically, when the cleaning is performed using a conventional non-halogen-based detergent composition or a polar or non-polar organic solvent, the flux residue derived from the tin salt may remain on the surface of the object to be cleaned due to the lack of cleaning power for the tin salt. The problem is that contaminants reattach. Accordingly, there is a demand for developing a lead-free solder flux cleaning composition for solving such problems.

The present invention is to solve the above problems of the prior art, and not only has a sufficient cleaning power for the lead-free solder flux adhering to the object to be cleaned, but also has a low impact on the object to be cleaned (corrosion, etc.) and an environmental load. It is an object of the present invention to provide a cleaning composition that is low, harmless to the human body, has low odor, and has low flammability.

The present invention

(a) a polymethyl alkyl siloxane surfactant represented by the following formula (1);

(b) tetrahydrofurfuryl alcohol represented by the following formula (2); And

(c) Provides a lead-free solder flux removal cleaning composition comprising a non-halogen organic solvent:

Where

R ₁ is hydrogen or an alkyl group having 1 to 8 carbon atoms.

The lead-free solder flux removal cleaning composition of the present invention not only has excellent cleaning power for the lead-free solder flux adhering to the object to be cleaned, but also has a low impact on the object to be cleaned (corrosion, etc.) and a low environmental load. Very effective for removal In addition, it is harmless to the human body, generates less odors, and has low flammability, so it is excellent in work safety.

Hereinafter, the present invention will be described in detail.

(A) Polymeryl alkyl siloxane surfactant contained in the lead-free solder flux cleaning composition of this invention is represented by following General formula (1).

[Formula 1]

Where

R ₁ is hydrogen or an alkyl group having 1 to 8 carbon atoms.

Examples of the alkyl key having 1 to 8 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, butyl group, pentyl group, hexyl group, octyl group, and the like, and methyl or ethyl group is more preferable.

The (a) polymethyl alkyl siloxane-based surfactant is used as an additive in the composition, it is oriented on the surface of the coating film to equalize the surface tension of the coating film to minimize the difference in surface tension, lower the surface tension, the wettability of the cleaner Improves cleaning aid.

The (a) polymethyl alkyl siloxane-based surfactant is preferably included in 0.001 to 5% by weight based on the total weight of the lead-free solder flux cleaning composition. More preferably, it is 0.001-2 weight%. When (a) the polymethyl alkyl siloxane-based surfactant is included in 0.001% by weight to 5% by weight, the surface tension of the coating film is uniform, thereby minimizing the difference in surface tension, lowering the surface tension, and also improves the wettability of the cleaning agent. The risk of occurrence is minimized, and the problem of extremely low surface tension does not occur.

Said (a) polymethyl alkyl siloxane type surfactant can be diluted and used for propylene glycol monomethyl ether acetate.

As a product commercialized as said (a) polymethyl alkyl siloxane type surfactant, Dow Corning Toray's SH-8400 (flash point: 191, specific gravity (25 degreeC): 1.03 g / ml, viscosity: 270 cSt) is mentioned.

(B) Tetrahydrofurfuryl alcohol contained in the lead-free solder flux cleaning composition of the present invention is represented by the following formula (2).

[Formula 2]

Tetrahydrofurfuryl alcohol (b) is used as a solvent in the lead-free solder flux cleaning composition, and serves to increase the dissolution rate of the lead-free solder flux.

The (b) tetrahydro furfuryl alcohol is preferably included in 1 to 90% by weight, more preferably 50 to 90% by weight relative to the total weight of the composition. When (b) tetrahydrofurfuryl alcohol is included in the above range, there is an advantage that the dissolving power is kept constant. In addition, when (b) tetrahydrofurfuryl alcohol (THFA) is included in 50% by weight to 90% by weight, the dissolution rate is kept constant, there is an advantage that almost no flux residue applied to the substrate remains. In addition, the (b) tetrahydro furfuryl alcohol does not include an amine group that can attack the lower material, there is an advantage that does not generate an attack (attach) to the lower material.

The (a) polymethyl alkyl siloxane-based surfactant and (b) tetrahydrofurfuryl alcohol (THFA) composition of the present invention have very improved cleaning power compared to THFA alone. It is therefore desirable to include at least 1% tetrahydrofurfuryl alcohol (THFA) in the composition.

The (c) non-halogen organic solvent included in the lead-free solder flux removal composition of the present invention is excellent with various solvents including the (a) polymethyl alkyl siloxane surfactant and (b) tetrahydrofurfuryl alcohol. It shows solubility. The non-halogen organic solvent (c) may be any known non-halogen-based organic solvent except for the (a) polymethyl alkyl siloxane surfactant and the (b) tetrahydrofurfuryl alcohol. For example, Hydrocarbon solvents, such as hexane, heptane, an octane; Alcohol solvents such as methanol, ethanol and propanol; Ketone solvents such as acetone and methyl ethyl ketone; Ether solvents such as diethyl ether, tetrahydrofuran and glycol ether compounds; Ester solvents such as ethyl acetate and methyl acetate; Nitrogen-containing compound solvents; Various well-known organic solvents, such as alkanolamine solvents, such as ethanol amine, monoethanol amine, and diethanolamine, can be used. In particular, the (c) non-halogen organic solvent may be used in combination of one or two or more selected from the group consisting of an alkanolamine solvent and a nitrogen-containing compound solvent in view of cleanability and the like.

As the nitrogen-containing compound solvent in the (C) non-halogen organic solvent, 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, N-propyl pyrrolidone, N-hydroxymethyl pyrrolidone and N-hydroxyethyl pyrrolidone Etc., These can be used 1 type or in mixture of 2 or more types, It is preferable to use 1-methyl- 2-pyrrolidone especially.

Alkanolamine solvents in the (C) non-halogen organic solvent include ethanolamine, diethanolamine, triethanolamine, monoethanolamine, isobutanolamine and ethylpropanediolamine, and these may be used alone or in combination. It is preferable to mix and use species, and it is preferable to use monoethanolamine.

The (C) non-halogen-based organic solvent is preferably contained in 1 to 20% by weight, more preferably 5 to 15% by weight based on the total weight of the composition. In the content range as described above, better removal performance is achieved for the lead-free solder flux.

The present invention also provides a method for removing lead-free solder flux using the composition for cleaning a lead-free solder flux. The washing | cleaning method at the time of removing a lead-free solder flux is not specifically limited, It can carry out by a well-known method using the cleaning composition of this invention. Hereinafter, the case where the cleaning composition of this invention is made to contact the lead-free cream solder flux on an electronic component as a general cleaning method is demonstrated.

As a specific washing | cleaning method, the method of directly immersing and cleaning an electronic component in the cleaning composition or aqueous solution of this invention, the method of spraying and washing the aqueous solution of the cleaning composition of this invention using a spray apparatus with respect to an electronic component, or this invention The cleaning composition of the present invention is brought into contact with an electronic component and brushed by mechanical means.

When cleaning the flip chip mounting substrate, the cleaning agent must be passed through a gap of 50 m or less of the substrate. Therefore, it can be performed by a direct cleaning method using a direct cleaning device. The direct-flow type washing device is a body part in a washing tower incorporated in a circulation line of a cleaning agent, and there is no fluid hole accommodated in a loosely fitted state, and the object to be cleaned has a liquid hole only at the bottom. The washing | cleaning apparatus which has a vertical cylinder for dragons. The direct cleaning method refers to a method of cleaning a to-be-cleaned object by forcibly distributing a cleaning agent in the tub after storing the object to be cleaned (flip chip mounting substrate) in a vertical tub of the washing apparatus.

The conditions for use (cleaning temperature, cleaning time, etc.) of the cleaning composition of the present invention are not particularly limited, and may be appropriately selected depending on the concentration and use ratio of each component (A) to (C) in the composition, the type of flux to be removed, and the like. have. For example, what is necessary is just to set the temperature of the said composition at the time of washing a to-be-cleaned object suitably so that the flux to be removed may be wash | cleaned and removed suitably. The temperature of the said aqueous solution is about 20-80 degreeC normally. The solubility of the flux with respect to the said aqueous solution can be improved by making the temperature of the said aqueous solution into 20 degreeC or more, and evaporation of water can be suppressed by making the temperature of the said aqueous solution into 80 degrees C or less. As for the temperature of the said aqueous solution, about 50-70 degreeC is more preferable.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are intended to illustrate the present invention more specifically, but the scope of the present invention is not limited by the following examples. The following examples can be appropriately modified and changed by those skilled in the art within the scope of the present invention.

Examples 1-7 and Comparative Examples 1-4: Preparation of lead-free solder flux removal

According to the composition ratio of Table 1 to the mixing tank equipped with a stirrer, after the addition of the components, and stirred at a speed of 500rpm for 1 hour at room temperature to prepare a lead-free solder flux cleaning composition.

division practice
Example 1 practice
Example 2 practice
Example 3 practice
Example 4 practice
Example 5 practice
Example 6 practice
Example 7 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 THFA 90 90 90 85 90 90 90 90 90 90 85 NMP One 3 7 3 One One One One One 3 3 MEA 8.7 6.7 2.7 11.8 8.9 8.7 8.7 7 12 MIPA 8.7 MMEK 8.9 SH-8400 0.3 0.3 0.3 0.2 0.3 0.1 0.1 PPG-1000 0.3 PPG-2000 0.3

THFA: tetrahydro furfuryl alcohol

NMP: 1-methyl-2-pyrrolidone

MEA: monoethanolamine

MIPA: monoisopropylamine

MMEK: mono methylethanolamine

SH-8400: (brand name: Dow Corning Torrey)

PPG-1000: Polypropylene Glycol, Wako Corporation

PPG-2000: Polypropylene Glycol, Wako Corporation

Test Example: Flux Residue Removal Test

After flux coating on a 4 inch silicon oxide substrate, the substrate is removed after heating at 230 ° C. for 60 seconds. The substrate is cut into 2 cm x 7 cm to make a test substrate.

The test substrate is treated in the following steps 1) to 3).

1) It is immersed in various cleaning composition (Examples 1-7, Comparative Examples 1-4) at 60 degreeC for 3 minutes.

2) Dip in DI water for 1 minute at 23 ° C.

3) Dry with nitrogen (N ₂ ) gas.

After the treatment as described above, the removal property of the flux of the cleaning composition of Examples 1 to 7 and Comparative Examples 1 to 4 was evaluated, and the results are shown in Table 2 below.

division Cleaning power Example 1 ◎ Example 2 ◎ Example 3 ◎ Example 4 ○ Example 5 ○ Example 6 ○ Example 7 ○ Comparative Example 1 △ Comparative Example 2 △ Comparative Example 3 △ Comparative Example 4 △

Note: Good removal of flux: Surface area of residue (flux) 0%

○: slightly remaining flux: more than 0% and less than 10% of the surface area of the residue (flux)

Δ: substantial amount of flux remaining: more than 10% of surface area of residue (flux)

division Surface tension Example 1 33.478 Example 2 34.58 Example 3 32.15 Example 4 33.54 Example 5 33.89 Example 6 34.12 Example 7 34.98 Comparative Example 1 38.12 Comparative Example 2 38.47 Comparative Example 3 41.07 Comparative Example 4 40.87

According to the test results of Table 2, the lead-free solder flux removal cleaning compositions of Examples 1 to 7 according to the present invention showed excellent performance in flux removal, whereas the cleaning compositions of the fluxes of Comparative Examples 1 to 4 were It was confirmed that the fall significantly.

In addition, according to the results of Table 3, the cleaning composition of Examples 1 to 7 shows a smaller surface tension than the cleaning composition of Comparative Examples 1 to 4 it was confirmed that the wettability is improved and the cleaning power is also improved.

Claims (4)

(a) a polymethyl alkyl siloxane surfactant represented by the following formula (1); (b) tetrahydrofurfuryl alcohol represented by the following formula (2); And (c) Lead-free solder flux removal detergent composition comprising a non-halogen organic solvent: [Formula 1]

Where R ₁ is hydrogen or an alkyl group having 1 to 8 carbon atoms. (2)

The method of claim 1, wherein the lead-free solder flux removal cleaning composition comprises (a) 0.001 to 5% by weight of a polymethyl alkyl siloxane surfactant, (b) 1 to 90% by weight of tetrahydrofurfuryl alcohol and (c) a non-halogen organic solvent. Lead-free solder flux removal cleaning composition comprising 1 to 20% by weight. The cleaning composition according to claim 1, wherein the (C) non-halogen organic solvent is one or two or more selected from the group consisting of alkanolamine solvents and nitrogen-containing compound solvents. The method of claim 3, wherein the nitrogen-containing compound solvent is 1-methyl-2-pyrrolidone, 1-ethyl-2-pyrrolidone, N-propyl pyrrolidone, N-hydroxymethyl pyrrolidone and N-hydroxyethyl pyrrolidone; The alkanolamine solvent is lead-free solder, characterized in that selected from the group consisting of ethanolamine, diethanolamine, triethanolamine, monoethanolamine, isobutanolamine, mono isopropylamine, monomethylethanolamine and ethylpropanediolamine Flux cleaning agent composition.